The present invention is directed toward an appliance capable of reducing or eliminating moisture damage to sensitive electronic devices such as hearing aids. Current trends in micro circuitry have enabled the production of hearing aids which reside partially or completely in the ear canal. This exposes the devices to a warm and moist environment and presents the opportunity for moisture damage to the circuits and possibly ultimate failure of the device. Additionally, for hearing-aid wearers residing in humid environments, moisture damage can occur even when the hearing aid is not being worn.
There are several means currently available to hearing aid wearers for protecting their devices from moisture damage while they are not being worn.
The simplest device is a jar with a screw-lid containing desiccant material inside and a piece of foam or other material separating the storage area from the desiccant.
A second device, as exemplified in U.S. Pat. Nos. 5,640,783 and 5,852,879, seeks to provide both drying and bactericidal activity. This device utilizes a fan to circulate air through the chambers of the unit. A heater is provided to assist in moisture removal, and sensing circuitry is required to ensure that the heater does not damage the hearing aids by raising the air to too high a temperature. The commercial embodiment of this invention is made to sit on a dresser or night-stand.
A third device (U.S. Pat. No. 6,399,920) provides warmed air, maintained below a critical temperature to avoid damaging the sensitive circuitry and a desiccant to absorb moisture liberated by the warmed air.
At some point, the desiccant material used in the above-described devices becomes depleted (saturated with moisture) and the user must either purchase another unit, supply fresh desiccant, or regenerate the desiccant material by heating it to a high temperature in a conventional or microwave oven. By conventional methods, the desiccant material is regenerated by exposure to high temperatures, in excess of 100 degrees Celsius. The process of regenerating is not only inconvenient, it presents a safety hazard to older patients who may lack the dexterity to safely handle the resulting hot desiccant material.
Therefore, there is a need in the field to provide a de-moisturizing appliance wherein the desiccant material is regenerated without the necessity of removal from the appliance.
We have surprisingly found, however, that the silica gel can also be regenerated by exposure to lower temperatures for longer periods of time. As will be disclosed below, the temperature of the desiccant bed remains below approximately 65 degrees Celsius, ensuring that the temperature at the surface of the container remains below approximately 57 degrees Celsius.
The available devices cannot regenerate the desiccant material. They only heat the chamber when the lid is closed, thereby not allowing the moisture in the desiccant to escape the appliance. The present invention works in the opposite way, with the lid open during operation of the heater.
It is the aim of the present invention to provide a simple to use, portable drying apparatus with a desiccant capable of being regenerated without removal. This invention eliminates the expense of purchasing fresh desiccant, as well as the inconvenience and safety hazards associated with regenerating the desiccant as required for currently available devices.